| Abstract: | A novel biodegradable unimolecular reversed micelle consisting of a poly(L ‐lactide) (PLA) shell and a hyperbranched D ‐mannan (HBM) core, that is, a chestnut‐shaped polymer (PLA–HBM), was synthesized by the polymerization of L ‐lactide on HBM with 4‐(dimethylamino)pyridine (DMAP) as the catalyst. The obtained polymers were soluble in dimethyl sulfoxide, tetrahydrofuran, and chloroform but insoluble in H2O. The molecular weights of the PLA chain on PLA–HBM tended to increase with increasing polymerization time. The number of PLA chains on PLA–HBM could be controlled by the ratio of DMAP to the sugar unit in HBM. The obtained copolymer, PLA–HBM, acted as a unimolecular reversed micelle with an encapsulation ability toward the hydrophilic molecule. In addition, the entrapped hydrophilic molecules were slowly released from the core of PLA–HBM, and the release rate was accelerated by the breaking of the PLA chains of the shell when proteinase K as a hydrolase of PLA was used. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 406–413, 2006 |
